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Part 1: Deformation
http://www.youtube.com/watch?v=DppbibMhAXU
Earth’s Changing surface
I. Crust – the surface layer of the earthA. Continental: land not under the oceansB. Average of 32km, but can be as thick as
70kmII. Oceanic
A. Ocean floorB. Average of 8km thick
Review: Which one is denser?
a. The forces that pull and push on the earth’s crustb. Causes deformation – the tilting, breaking or folding of rock
III. STRESS
i. Compression
Compression – squeezes the rocks of the
crust, decreasing
volume, increasing
density
Think: Covergent
ii. Tension
Tension – pull the rocks of the crust, increasing volume,
decreasing density Think: Divergent
iii. Shearing
Shearing – the crust being pushed in opposite directions
causing the rocks to tear
and twistThink: transform
Review #1. Match the set of arrows to the 3 stress
a. Shearing
b. Tension
c. Compression
Fractures and Faults
c. Fracture – cracks in rocks
d. Fault – crack along which rocks move sideways, up, or down.i. Fault block mountains form from
the normal faults pushing up rockii. Rift valleys form when land
between normal faults slide down
San Andres
Folding
e. Folding – a bend in the rocki. Anticline – an upward foldii. Syncline – a downward foldiii. Appalachian mountains are made from folds
The Appalachians
f. Factors that affect faulting or folding
i. Higher temperatures will cause folding/lower temps. cause faultingii. Greater pressure causes folding/lower pressure causes faulting
Rock typeiii. Brittle rock will more likely faultiv. Ductile (bendable) rock will more likely foldv. Pressure applied gradually will cause folding/fast will cause faulting
Review #2
What’s the difference between anticline and
syncline folding?!